A software defined network (SDN) refers to a network architecture in which control and data planes are decoupled. The control plane is centralized into a controller and the data plane is responsible for traffic forwarding. In the SDN, the centralized controller decides where and how traffic is routing. The control plane performs a function of controlling a network, and the data plane performs a function of forwarding data.
The openflow protocol is a protocol that enables SDN technology and its standardization is already in progress. The openflow protocol defines only how to send the traffic, and what benefit is obtained by the openflow protocol by itself is not clear. Until now, the openflow protocol is mainly applied to switches that connect servers in a data center, and how the openflow protocol is applied to a Long Term Evolution (LTE™) network is not yet discussed actively. Of cause, how the openflow protocol is applied to Voice over LTE (VoLTE) is not yet discussed actively.
The VoLTE is a technology of allowing voice calls to be made using packets on an LTE™ network. The VoLTE sets up a bearer for voice forwarding after attachment of an UE, and allows voice packets to be forwarded preferentially by setting the priority of the bearer to a higher value than others.
However, the VoLTE is based on a basic LTE architecture. That is, voice packets are forwarded to an evolved packet core (EPC) of a core network and the EPC forwards the voice packets to a target receiver. Therefore, there is no efficiency in forwarding of voice packets.
Even when a transmitter and a receiver are served by evolved NodeBs (eNBs) adjacent to each other, the above-described process is performed, leading to inefficiency in forwarding of voice packets.